Water and carbon dioxide are generally immiscible under normal environmental conditions, i.e., room temperature and atmospheric pressure. Apparatuses and methods are known for producing carbonated water by creating conditions under which carbon dioxide will become water-soluble. Generally, carbon dioxide becomes more soluble in water as pressures increase and temperatures decrease.
Most commercialized devices for carbonating water use carbon dioxide sprayed into a water container: the result obtained with this process is very poor and the carbonation of water is weak and does not last too long. Devices for producing and dispensing carbonated beverages in water dispensing units, instead, typically employ a carbonating tank, called a saturator, and a high-pressure water pump. Carbonated water is produced by pressurizing the saturator tank with carbon dioxide and filling the tank with chilled water. Due to the high pressures resident in the saturator tank, typically around 70 psi, a relatively expensive high-pressure water pump is required to inject water into the tank. Furthermore, under the conditions in the saturator tank, the carbon dioxide takes time to dissolve into to the water and achieve a palatable level of carbonization. Accordingly, the saturator is typically large enough to hold a ready supply of carbonated water for dispensing and does not create new carbonated water instantaneously on demand. To maintain this supply, two or more sensors—and associated electronic controls—are used to start the high pressure pump and inject water into saturator when the level of carbonated water in the saturator falls below a set threshold and then stop the water injection when the tank fills to an appropriate level.
These typical carbonization devices take up a relatively large amount of space and require expensive and complicated electronic and hydraulic control systems. Due to this complex structure, these devices are noisy, use significant amounts of energy, and require frequent maintenance.